Pipe sealing tool with external clamp

ABSTRACT

An apparatus for sealing an open end of a pipe includes a clamp for frictionally being secured to the exterior of the pipe, a sealing plate for covering the open end of the pipe and being connectable to the clamp, and an urging mechanism for urging the sealing plate towards the clamp and for forming a seal between the sealing plate and the open end of the pipe. In one aspect, the clamp comprises an annular body formed by at least two sections that are radially tightened over the pipe exterior. In another aspect, the clamp comprises cooperating annular bodies, one capable of radially narrowing the other for frictionally engaging the pipe outer surface. In another aspect the method provides a method of sealing an end of a pipe. According to the invention, once the open end is sealed, the interior of the pipe may be pressurized, for example for testing the integrity thereof.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a Continuation in Part of U.S. application Ser. No.12/098,273 filed on Apr. 4, 2008, now U.S. Pat. No. 7,669,899, issued onMar. 2, 2010, which is a Continuation of PCT application numberPCT/CA2006/001641 filed on Oct. 6, 2006, which claims priority from U.S.Provisional application No. 60/723,915, filed Oct. 6, 2005. The entirecontents of all the aforementioned related applications are incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to an apparatus for sealing an open end ofa pipe using an externally mounted clamp. Once sealed, the pipe can besubjected to pressurization for testing purposes etc.

BACKGROUND OF THE INVENTION

In chemical or petrochemical plants etc., it is often necessary toconvey fluidic materials (e.g. liquids) from one location to another.The conveyance of such material normally includes equipment such asconduits or pipes, storage or reaction vessels etc., which are generallymanufactured from metal. The joining of separate pieces of the conveyingequipment is generally achieved by welding the necessary piecestogether. For example, when joining adjacent ends of pipe together, itis common for each end to be provided with flanges, that are welded toeach respective end, which are then bolted together to form a seal. Suchflanges may also be provided on holding tanks and other such vessels sothat such vessels can be connected to pipes or other vessels.Alternatively, the connections between lengths of pipe or otherequipment may be welded directly together (i.e. butt welded) to form theseal. In either case, it will be appreciated that each welded joint orsection must form a complete seal so as to prevent leakage of thematerials being transported. This is particularly the case when handlingpotentially hazardous materials such as flammable or toxic liquids.

For reasons of safety, it is often necessary to periodically test theintegrity of the welds used in joining the various pieces of equipment(such as pipes, vessels, flanges and the like) together.

The prior art provides various tools for conducting weld integrity testson conduits. For example, U.S. Pat. Nos. 6,131,441 and 5,844,127 (theentire disclosures of which are incorporated herein by reference) teachweld testing tools that isolate a particular section of a pipe (suchsection including a weld) and subject the section to a high pressurefluid within a constrained annular space defined by the tool and theinner surface of the pipe. The pressure of the fluid within the annularspace is monitored whereby any pressure drop signifies a leak in theweld.

U.S. Pat. No. 6,463,791 (the entire disclosure of which is incorporatedherein by reference) teaches an apparatus for testing welds used tosecure nozzles. As shown in FIG. 1 of this reference, the apparatuscomprises a first seal plate that is placed on the inner surface of thevessel (for example) and a second seal plate that is secured to theouter, flange portion of the nozzle. In this manner, the nozzle volumeis sealed and a pressurizing fluid is introduced therein. Once thevolume is filled, the pressure is monitored as above and any leakagedetected. Although this apparatus provides an accurate and efficientmeans of testing welds on nozzles, the size and weight of the apparatusmakes it inconvenient for use on large nozzles.

Further, applicant's co-pending U.S. application Ser. No. 11/771,158(publication number US 2008/0121044), provides tools for testing theintegrity of welds on pipes and the like. The entire disclosure of suchapplication is incorporated herein by reference.

There exists a need for more easily sealing a section of a long pipe forconducting the type of stress tests mentioned above. In addition, thereexists a need for an apparatus that is capable of exerting axialstresses on welds during such testing so as to simulate a “worst casescenario”. In particular, there is a need for an apparatus that can beeasily mounted on an open end of a pipe so as to effectively seal thepipe opening and maintain such seal during high pressurization of thepipe. Such apparatus would not subject the pipe to any damage orotherwise cause weakness thereto.

SUMMARY OF THE INVENTION

In one aspect, the present invention generally provides an apparatus forsealing an open end of a pipe comprising:

-   -   at least one generally annular shaped clamp for being        frictionally secured to an outer surface of the pipe, adjacent        and spaced from the open end thereof, the at least one clamp        including a means for circumferentially gripping the outer        surface of the pipe and preventing relative axial movement        there-between;    -   a sealing plate, adapted to cover the open end of the pipe, the        sealing plate including a means for sealing the open end of the        pipe;    -   an urging means for urging the sealing plate axially towards the        at least one clamp and against the open end of the pipe.

In another aspect, the invention provides an apparatus as above andwherein:

-   -   the at least one clamp is comprised of at least two clamp        sections, adapted to be joined together to form an annular body        adapted to fit over the exterior surface of the pipe;    -   each of the clamp sections including connecting flanges,        provided at opposite ends of the sections, the flanges having a        plurality of bolt holes;    -   a plurality of second connecting elements for connecting flanges        of adjacent clamp sections and for tightening each clamp section        towards adjacent clamp sections for forming said annular shaped        clamp.

In another aspect, the invention provides an apparatus as above andwherein the at least one clamp includes:

-   -   a generally annular body having an inner diameter surface, at        least a portion of the inner diameter surface including a first        ramp extending from a first end to a second end of the annular        body, the annular body having an inner diameter that is greater        at the first end than at the second end;    -   a generally annular gripper ring, coaxial with the annular body,        the gripper ring being comprised of two or more sections, and        having an inner surface with an inner diameter for engaging the        outer surface of the pipe, and an outer surface, at least a        portion of the outer surface of the gripper ring including a        second ramp, the second ramp extending from a first end of the        gripper ring to a second end of the gripper ring, the second        ramp being oppositely directed to the first ramp, wherein the        second end of the gripper ring is insertable within an annular        space between the first end of the annular body and the outer        wall of the pipe; and,    -   a means for urging the gripper ring and the main body towards        each other for forcing the second ramp under the first ramp,        whereby, when the apparatus is in use, the first ramp bears        against the second ramp wherein the inner diameter of the        gripper ring is reduced resulting in a frictional engagement        between the gripper ring and the outer surface of the pipe.

In another aspect, the invention provides a method for sealing a sectionof a pipe having an open end, the method comprising:

-   -   positioning at least one external clamp circumferentially over        the outer surface of the pipe at a location spaced away from the        open end, the at least one clamp being frictionally secured to        the pipe surface so as to prevent relative axial movement        between the clamp and the pipe;    -   positioning a sealing plate against the open end of the pipe,        for covering the open end, the sealing plate including a groove        adapted to receive the open end of the pipe;    -   connecting the sealing plate to at least one of the at least one        clamps;    -   forcing the sealing plate axially towards the at least one clamp        and forming a seal between the open end of the pipe and the        sealing plate.

In another aspect, the invention provides a method as above and whereinthe at least one clamp comprises a generally annular body formed of atleast two sections, and wherein the step of securing the external clampcircumferentially over the outer surface of the pipe comprisesconnecting the at least two sections together and tightening thesections to cause frictional engagement between the at least one clampand the pipe outer surface.

In another aspect, the invention provides a method as above and whereinthe at least one clamp comprises: a generally annular body having aninner surface, a portion of the inner surface comprising a first ramp;and, a generally annular gripping ring formed of at least two sections,said gripper ring including an outer surface, a portion of the outersurface comprising a second ramp; the method comprising:

-   -   coaxially positioning the annular body and the gripper ring over        a pipe such that the first and second ramps are oppositely        oriented, wherein the second ramp of the gripper ring is        insertable between the first ramp of the annular body and the        outer wall of the pipe;    -   forcing the gripper ring against the annular body to cause        radial compression of the gripper ring and frictional engagement        of the gripper ring over the pipe outer surface; and,    -   forming a sufficient clamping force between the gripper ring and        the pipe surface to prevent relative axial movement between the        at least one clamp and the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent inthe following detailed description in which reference is made to theappended drawings wherein:

FIG. 1 is a cross sectional view of one embodiment of the apparatus ofthe present invention.

FIG. 2 is a perspective view of the clamp of the apparatus of FIG. 1.

FIG. 3 is a cross sectional elevation of another embodiment of the clampof FIG. 1.

FIGS. 4, 4 b, 5 and 6 are cross sectional views of further embodimentsof the present invention.

FIGS. 7 to 9 are cross sectional views of an embodiment of the inventionhaving an external clamp.

FIG. 10 is a perspective view of another aspect of the invention shownin FIG. 9.

FIG. 11 is side view of another aspect of the invention shown in FIG.10.

FIG. 12 is an end view of a clamp shown in FIGS. 10 and 11.

FIG. 13 is a side cross-sectional view of another embodiment of theexternal clamp according to the invention.

FIG. 14 is an end view of the embodiment shown in FIG. 13.

FIG. 15 is a side cross-sectional view of another embodiment of theexternal clamp according to the invention.

FIGS. 16 and 17 are front and side cross-sectional views of the squeezering shown in FIG. 15.

FIGS. 18 and 19 are front and side cross-sectional views of the clampingring shown in FIG. 15.

FIGS. 20, 21 and 22 are front, side cross-sectional and detailedcross-sectional views of the gripper ring shown in FIG. 15.

FIG. 23 is a side cross-sectional view of an embodiment of the inventionshown in FIG. 15 wherein a plurality of external clamps are combined.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the description of the invention the following terms will beassumed to have the following associated meanings:

“Vessel”—will be understood to mean any equipment or apparatus to whicha nozzle is attached. As such, the term “vessel” will include vesselsper se, pipes, drums, and any other similar equipment. It will beunderstood that the term “vessel” is used herein simply as a convenientway to encompass all such equipment or apparatus.

“Annular”—this term is used to describe a body having at least one outerdiameter and at least one inner diameter. Thus, an “annular tube” willbe assumed to be a hollow tube with an inner and outer diameter. An“annular disc” will be assumed to be an object having an outer diameterand a central aperture thereby providing an inner diameter.

“Axial”—this term will be used to describe a direction taken along thelongitudinal axis of a pipe or conduit. Thus, “axial force” or “axialstress” will be understood as being a force applied in a directionparallel to the longitudinal axis of the conduit. Similarly, the term“axially extending” will be understood to mean extending in a directionparallel to the longitudinal axis of the pipe.

“Proximal” and “distal”—these terms will be used to describe thepositions of various components of the invention once positioned over apipe having an open end. The term “proximal” will be used to describe aposition closer to the open end of the pipe. The term “distal” will beused to describe a position away from the open end of the pipe.

FIG. 1 illustrates one aspect of the invention wherein an internalsealing apparatus for a pipe is shown. The sealing apparatus 10 ispreferably sized to fit within the lumen of a pipe (or tube) 12. Theapparatus 10 comprises a sealing plate 14 having a diameter slightlyless than the internal diameter of the pipe 12. The plate includes afirst face 16 and a second face 18, wherein the second face is adjacenta clamp 20. The second face 18 of the sealing plate 14 is provided withbeveled edge 22 for accommodating an O-ring 24 or other such resilientsealing means.

The clamp 20 generally comprises an annular ring having an outerdiameter sized to fit within the pipe 12. An annular shape for the clamp20 is preferred to minimize its weight. However, the clamp 20 may alsocomprise a solid body. As will be understood by persons skilled in theart having reviewed the present disclosure, the outer diameter of theclamp 20 is preferably slightly less than the internal diameter of thepipe 12 so as to permit axial placement of the clamp 20. The clamp 20 isprovided with one or more recesses or pockets 26 into which are placedmagnets 28. Preferably, the magnets 28 comprise electromagnets that canbe activated when desired.

The magnets 28 provided on the clamp 20 are designed to magneticallyattract the wall of the pipe 12, which, as is commonly known in the art,is formed from a ferrous metal. The magnets 28 are designed to form astrong clamping force with the interior wall of the pipe 12 and,thereby, to anchor the clamp in a fixed axial position within the pipe12. In a preferred embodiment, at least two or more magnets 28 areprovided on the clamp 20 with such magnets being placedcircumferentially around the annular clamp 20. Such an arrangement willserve to evenly secure the clamp 20 within the pipe 12. Although thepresent description refers to a number of magnets being provided on theclamp, in other embodiments, one or more shaped magnets can be providedso as to achieve the desired clamping force.

The clamp 20 is releasably secured to the sealing plate 14. In oneembodiment, the clamp is provided with one or more, and preferably aplurality, of bolts 30 adapted to be inserted into holes 31 provided onthe sealing plate. Nuts 32 cooperate with the bolts 30 to secure thesealing plate 14 to the clamp 20. It will be understood that a sealingmeans (not shown) may be provided between the bolts 30 and the nuts 32and/or holes 31 in the sealing plate 14 to provide a seal and, thereby,prevent leaks through the holes 31.

FIG. 2 illustrates an embodiment of the clamp 20 illustrating thecircumferential placement of the magnets 28 and the bolts 30. Asmentioned above, although the clamp 20 is shown in FIG. 2 in the form ofan annulus, it may also comprise a solid body. In either embodimentcase, in order to reduce the weight of the clamp 20, it may be formed ofa light material such as aluminum. The sealing plate 14 may also beformed of aluminum. However, it will be understood that the choice ofmaterial for the clamp 20 and/or the sealing plate 14 may be chosen froma variety of others.

As can be seen in FIG. 1, upon tightening of the nuts 32, the sealingplate 14 is forced against the opposing face of the clamp 20. In thecourse of this process, the resilient seal 24 (i.e. the O-ring) iselastically deformed. The bevel 22 provided on the sealing plate 14causes such deformation to expand radially outwardly.

In use, the apparatus 10 is first inserted within a pipe 12. Theapparatus 10 is axially positioned in a desired location within the pipe12. It will be understood that the apparatus may be preassembled priorto the positioning step. That is, the sealing plate 14 may be looselyconnected to the clamp 20. Alternatively, the sealing plate 14 and clamp20 may be inserted separately within the pipe 12. Once the apparatus 10is positioned at the desired location, the sealing plate 14 is connectedto the clamp 20 (if not already) by first inserting the bolts 30 throughthe holes 31 and attaching the cooperating nuts 32 thereto. As mentionedabove, any type of seal (such as washers, packing etc.) may also beprovided so as to seal the holes 31. Tightening of the nuts 32 forcesthe sealing plate 14 against the clamp 20 and, as discussed above,results in the outward radial deformation of the seal 24. The seal 24 isthereby forced against the inner wall of the pipe 12 resulting in apressure resistant seal there-between.

Either before the tightening of the nuts 32 or after, the magnets 28provided on the clamp 20 are activated resulting in a strong attractionforce being formed between the magnets 28 and the wall of the pipe 12.It will be understood that the magnets used in the invention are chosenso as to provide the required clamping force to prevent axial movementof the clamp 20 within the pipe 12. As mentioned above, the magnets 28preferably comprise electro magnets. In such case, one or more powersupply units (not shown) will be connected to the magnets 28 in order toactivate same.

Once the clamp 20 is secured to the pipe 12 and the sealing plate 14 issecured and sealed against the clamp 20, the lumen of the pipe 12 facingthe first face 16 of the sealing plate may then be pressurized with agas or liquid without leakage beyond the sealing plate 14.

FIG. 3 illustrates another embodiment of the clamp 20 having an annularstructure wherein an inwardly extending flange 34 is provided toaccommodate the bolts 30. The bolts may be permanently attached to theflange 34 (or the face of the clamp 20) by means of welds etc., may beintegrally formed therewith, or may extend there-through and be securedwith nuts (not shown).

FIG. 4 illustrates the use of the sealing apparatus of the invention forthe dual purposes of sealing and testing a pipe. As shown, a pair ofapparatuses 10 a and 10 b is provided within a pipe 12 and positioned onopposite sides of a weld 36, the integrity of which is to be tested.Apparatus 10 a is essentially identical to that shown in FIG. 1 and asdescribed above. As discussed above, apparatus 10 a includes a sealingplate 14 a joined to a clamps 20 a by means of nuts and bolts 32 a and30 a, respectively. Clamp 20 a includes at least one magnet 28 a, andpreferably two or more magnets generally circumferentially equidistantlyspaced. A seal is formed between the apparatus 10 a and the inner wallof the pipe 12 by means of a resilient seal 24 a, which may comprise anO-ring. The magnets 28 a are activated to secure the clamp to the pipe12 at the desired location. As explained above, such securing resultswhen the attraction force of the magnets creates a tight frictionengagement between the magnet and the pipe 12 surface.

Apparatus 10 b of FIG. 4 is similar to the apparatus 10 a describedabove and similar elements are identified with similar referencenumerals but with the letter “b” added for clarity. As shown, apparatus10 b is positioned within the pipe 12 on the opposite side of the weld36 from apparatus 10 a. In this manner, the two apparatuses 10 a and 10b combine to seal off a section of the pipe 12 thereby forming a sealedspace 37. In the case of apparatus 10 b, the sealing plate 14 b isprovided with at least one fluid port 38 through which the sealed space37 can be filled with a pressurizing fluid (i.e. a liquid or a gas). Ina preferred embodiment, as illustrated in FIG. 4, two ports 38 areprovided so that one is used to fill the space 37, for example withwater, while the other is used to vent any air there-within. It will beappreciated that any number of ports 38 can be provided. One or more ofthe ports 38 is preferably connected to a pressure gauge or othersimilar device (not shown) to monitor the pressure created within thespace 37. As will be known to persons skilled in the art, a test of theweld 36 involves applying a constant high pressure to the interior ofthe pipe and monitoring such pressure over a period of time. Any drop inpressure signifies a leak in the weld.

In use, the system illustrated in FIG. 4 first involves placing andsecuring the apparatuses 10 a and 10 b in the manner described above.The sealed space 37 is then filled with a pressurizing fluid and, asdescribed above, the pressure is monitored.

Apart from the testing function provided by the system shown in FIG. 4,a further feature of the invention will also be understood.Specifically, by creating a sealed pressurized space 37 between theapparatuses 10 a and 10 b, it will be seen that the pressure applied tothe weld 36 also provided a separating force between the twoapparatuses. However, since the apparatuses are secured, or clamped, tothe interior of the pipe, such separating force also serves to apply anaxial force against the weld 36. In this way, the system shown in FIG. 4applies both radial and axial forces against the weld 36 thereby moreaccurately simulating a “worst case” scenario for conducting the weldtest. It will be understood that such simulated stresses will providemore accurate results for the test.

FIG. 4 b illustrates a variation of the assembly shown in FIG. 4. In thecase of FIG. 4 b, the apparatus 10 a and 10 b are essentially the sameas that discussed above in that each includes at least one clamp 20 aand 20 b, respectively, which are provided within a pipe 12. Clamps 20 aand 20 b include magnets 28 a and 28 b arranged in the same manner asdescribed above. The main difference between the assembly shown in FIGS.4 and 4 b lies in the sealing plates 14 a and 14 b. In the case of FIG.4 b, the sealing plates 14 a and 14 b are general of an annular discshape, wherein each includes a generally central opening. As will beappreciated by persons skilled in the art, this allows the plates 14 aand 14 b to be of much reduced weight thereby facilitating use of theassembly in large diameter pipes.

In addition, the sealing plates 14 a and 14 b of FIG. 4 b are joinedtogether by a tube 15 extending between each plate. The tube 15 includesan inner diameter that is preferably larger than the diameters of theopenings provided in plates 14 a and 14 b. Further, the outer diameterof the tube 15 is less than the inner diameter of the pipe 12. When theassembly of apparatuses 10 a and 10 b is installed within a pipe 12, asealed annular space 35 is thus formed between the two seals 24 a and 24b, the outer surface of the tube 15 and the inner surface of the pipe12. The tube 15 is also preferably provided with one or more ports asdiscussed above. In FIG. 4 b, two ports, 38 and 38′ are shown. The portsare used to fill and/or vent the annular space 35 in the same manner asdescribed above. As can be seen, the volume of the space 35 is minimizeddue to the presence of the tube 15 and, therefore, the volume of fluidrequired to fill the space is minimized.

FIG. 5 illustrates the use of a sealing apparatus of the invention in amanner similar to that shown in FIG. 4. In the example illustrated inFIG. 5, a weld 40 is used to secure a flange 42 to the end of a pipe 12.It will be understood that pipe 12 may be a pipe used for conveying asdescribed above or may be the conduit portion of a nozzle provided on avessel and the like. In this example, an apparatus 10 c essentially thesame as that shown in FIG. 1 is used to seal the pipe 12 on one side ofa weld 40 opposite to the flange 42. In FIG. 5, the elements ofapparatus 10 c that are similar to the apparatus of FIG. 1 are shownwith the same reference numerals but with the letter “c” added forclarity. The method of positioning and sealing the apparatus 10 c is thesame as described above. In this example, the open end of the flange 42is sealed with a plate 44. The plate 44 is formed with a series ofcircumferentially spaced bolt holes that correspond with bolt holes thatare normally present on the face of the flange 42. Once the bolt holesof the plate 44 are aligned with those of the flange 42, bolts 45 areinserted there-through and secured with nuts 46. As shown in FIG. 5,nuts may be provided on both ends of the bolts 45. It will be understoodthat the bolts 45 may have one end with an integral or welded bolt headthereby avoiding the need for nuts on both ends thereof. It will beunderstood that any needed seal such as a gasket and the like (notshown) may be provided at the junction of the faces of the flange 42 andplate 44.

The plate 44 is provided with at least one port 38 c in a manner similarto that described above with reference to FIG. 4. The ports 38 c serveto fill the sealed space 37 c between the flange 42 and the sealingapparatus 10 c. As shown in FIG. 5, the sealed space 37 c includes theweld 40 that secures the flange 42 to the end of the pipe 12.

In using the system shown in FIG. 5, the sealing apparatus 10 c is firstinstalled within the pipe 12 in the manner described above. The plate 44is then installed at the outer face of the flange 42. The plate 44 issecured to the flange 42 so as to form a pressure tight sealthere-between. As mentioned above, any needed gaskets etc. can be usedfor this purpose. Once the plate 44 and the apparatus 10 c are securedand clamped, a pressurized fluid is injected through one or more of theports 38 c so as to pressurize the space 37 c. As discussed above withrespect to FIG. 4, the apparatus shown in FIG. 5 also serves to applyboth a radial as well as axial stress on the weld 40.

FIG. 6 illustrates a further embodiment of the invention wherein theapparatus 10 of FIG. 1 is provided within a pipe 12. However, in thisexample, the exterior surface of the pipe is provided with a retainingcollar 48 comprising a generally annular body having an inner and outerdiameter. The inner diameter of the collar 48 is provided with a numberof circumferentially spaced magnets 50 designed to abut the outersurface of the pipe 12. The magnets 50 of the collar 48 are arranged soas to overlap magnets 28 provided on the clamp 20 when the collar 48 ispositioned in the same axial position as the clamp 20. The magnets 50 ofthe collar 48 may be provided with a different power source or the sameas that powering magnets 28 of the clamp 20.

With the embodiment of FIG. 6, it will be understood that thecombination of the magnetic attraction forces of both sets of magnets 28and 50 will serve to provide an enhanced clamping force for theapparatus. In other words, the collar 48 serves to reinforce the clamp20. In a further embodiment, the polarity of the magnets 28 and 50 canbe adjusted so as to form a magnetic attraction force there-between. Inthis manner, the combination of the clamp 20 and collar 50 can be usedwith non-ferrous pipes as well such as pipes made from aluminum orstainless steel etc. In such case, it will be understood that themagnets 28 and 50 will be provided with a pipe contact surface having asufficient coefficient of friction to prevent the apparatus from slidingover the pipe 12. Similarly, even in the case of ferrous pipes, such afriction surface may be provided on the magnets 28 and/or 50.

It will be understood that the collar 48 may be used with any of theclamps discussed above.

FIG. 7 illustrates a further embodiment of the invention for sealing anend of a pipe. As shown a pipe 12 having an open end 52 is provided withan end plate 54 adapted to close the open end. The end plate 54 ispreferably provided with a circular race 56 for receiving therein theend 52 of the pipe 12. As will be understood, the width of the race 56will generally be sized to accommodate the thickness of the pipe 12. Therace 56 is also preferably provided with a resilient sealing member 58so as to form a seal between the plate 54 and the end 52 of the pipe 12.

The plate 54 is provided with diameter greater than that of the pipe 12so as to form a radially extending anchoring flange 60. In anotherembodiment, the plate 54 may have a diameter closer to that of the pipe12 but be provided with radially extending arms to form an equivalent tothe anchoring flange 60.

The anchoring flange 60 is provided with a plurality ofcircumferentially spaced bolt holes 62 through which are passed bolts64. On the face of plate 54 opposite the pipe end 52, the bolts 64 aresecured with nuts 66. The opposite ends of the bolts 64 are secured to aclamping collar 68 comprising a generally annular body circumferentiallyextending around the external surface of the pipe 12. The clampingcollar 68 includes a radially outwardly extending flange 70 facing theplate 54. The flange 70 is provided with a plurality of bolt holes 72corresponding to the bolt holes 62 on the plate 54 and adapted toreceive the opposite ends of the bolts 64. The flange 70 is secured tothe bolts 64 with nuts 74. In another embodiment, it will be understoodthat the bolts 64 can be welded or formed with either the plate 54 orthe flange 70 thereby requiring only one set of nuts 66 or 74.

The clamping collar 68 is provided with one or more magnets 76circumferentially around the inner diameter thereof and directed towardsthe outer surface of the pipe 12. The magnets 76 are provided withinrecesses or pockets 77 provided in the body of the collar 68. Asdiscussed above, the magnets 76 may preferably comprise electro magnetscoupled to one or more power sources (not shown). In a preferredembodiment, a plurality of magnets 76 are provided generallyequidistantly around the circumference of the pipe 12 so as to evenlydistribute the associated clamping forces.

In another embodiment, the clamping collar 68 may be provided in one ormore sections.

In operation, the clamping collar 68 is mounted on the outer surface ofthe pipe 12. At this time, the magnets 76 may be activated so as to forma magnetic attraction force between the magnets and ferrous pipe 12. Thestrength of the magnets will be chosen so as to form an adequateclamping force between the collar 68 and the pipe 12 so as to preventrelative axial movement there-between. As mentioned above, the magnets76 may be provided with a friction enhancing surface to assist inpreventing relative axial movement between the collar 68 and the pipe12.

Once the clamping collar 68 is secured to the pipe 12 surface, the plate54 is then mounted against the open end 52. The plate is mounted so thatthe end of the pipe 12 is received within the race 56. At this time, thebolts 64 are positioned and secured with bolts 66 and 74. As will beunderstood, tightening of the bolts results in the plate being forcedagainst the open end 52 of the pipe 12 and, thereby, the end of the pipebeing sealed.

Once the end of the pipe 12 is sealed with the plate 54, the interior ofthe pipe can then be pressurized to test, for example, any weldsprovided on the pipe.

In a further embodiment, as shown in FIG. 8, the plate illustrated inFIG. 7 can be provided with ports 39, which are similar to those shownas element numbers 38 c in FIG. 5. As will be understood, the apparatusshown in FIG. 8 can be used to pressurize the interior of the pipe 12 soas to apply a radial and axial stress therein. In this manner, a weld onthe pipe, downstream of the end 52 may be tested with the apparatus ofFIG. 8 without the need to localize the testing apparatus at the regionof the weld. It will also be understood that the apparatus of FIG. 8 canused in combination with, for example, the sealing apparatus 10 or 10 cof FIG. 1 or 5 so as to isolate a segment of a pipe for testingpurposes.

A further embodiment of the apparatus of FIGS. 7 and 8 is illustrated inFIG. 9 wherein like elements are indicated with like reference numerals.Elements that are similar but not identical are indicated with likereference numerals but with the letter “d” added for clarity. As can beseen, in the embodiment of FIG. 9, the clamping collar 68 d does notinclude any magnets for engaging the wall of the pipe 12. In the exampleof FIG. 9, the clamping collar 68 d is provided in two or more sectionsthat are joined together by means of cooperating radially extendingflanges 78. Each of the flanges 78 are provided with bolt holes 80through which bolts (not shown) are passed. Nuts (not shown) cooperatewith the bolts to join opposing flanges 78 together thereby securing theflanges together. The clamping collar 68 d of FIG. 9 is sized so thattightening of the flanges 78 to each other forms a strong frictionalengagement with the outer surface of the pipe 12.

As discussed above with respect to other aspects of the invention, oncethe clamping collar, or clamp 68 d is secured to the outer surface ofthe pipe, a sealing plate 54 may be secured to open end of the pipe 12.In the same manner as described above, the sealing plate 54 is securedto the clamp 68 d by means of an urging means. In the embodiment shown,such urging means is provided by a combination of nuts and bolts thatjoin the clamp 68 d to the sealing plate. Tightening of such nuts urgesthe sealing plate 54 towards the clamp 68 d. In view of the frictionalengagement of the clamp 68 d to the outer surface of the pipe 12, it isprevented from movement with respect to the pipe 12. In particular,relative axial movement of the clamp 68 d and the pipe 12 is prevented.In the result, the sealing plate 54 is pressed against the open end ofthe pipe 12 and, thereby seals such open end in the same manner asdescribed above.

FIG. 10 illustrates a further aspect of the invention wherein a clamp isprovided on the outer surface of a pipe, adjacent an open end ofthereof, and a sealing plate (or other similar means) is provided toseal the open end of the pipe. In the embodiment shown in FIG. 10, theclamp 90 is similar in design to that shown in FIG. 9. However, asillustrated, the clamp 90 is formed of a plurality of sections 92 a, 92b, 92 c etc., which are adapted to be joined together to form acircumferential collar (i.e. the clamp 90) around the surface of a pipe12. In FIG. 10, only sections 92 a, 92 b, 92 c are shown. However, itwill be understood that the clamp 90 shown in FIG. 10 includes othersections that extend on the opposite side of the pipe shown therein. Itwill also be understood that the number of sections forming the clamp 90will depend on the size (i.e. length) of each section and the outerdiameter of the pipe. For example, for small diameter pipes, only twosections may be needed (as shown in FIG. 9). However, for largerdiameter pipes such as that shown in FIG. 10, the clamp 90 may beprovided in several sections.

The sections forming the clamp 90 are provided with a pair of radiallyextending, longitudinal “connecting” flanges, one at each end of theclamp section. The term “radially extending, longitudinal” refers to theorientation of the flanges when the clamp 90 is in use on a pipe. Theterm “connecting” refers to the use of such flanges in connectingadjacent clamp sections together. As shown and described further below,the connecting flanges extend radially outwardly away from the pipe 12.Further, these flanges extend in a direction parallel with thelongitudinal axis of the pipe 12. As shown in FIG. 10, clamp section 92b is shown with flanges 94 b and 95 b at the opposite ends thereof. Eachof the connecting flanges extend in the same direction, perpendicularlyto the body of the respective section. When the clamp 90 is assembled,as shown in FIG. 10, the flanges extend radially outwardly, away fromthe pipe, and extend in a direction generally parallel to thelongitudinal axis of the pipe 12. As shown, when the clamp 90 is in theassembled state over a pipe 12, the flanges of each adjacent section ofthe clamp 90 abut each other. For example, as shown in FIG. 10, theflange 94 b of section 92 b is positioned in facing arrangement againstflange 95 a of section 92 a. Similarly flange 95 b is positioned infacing arrangement against flange 94 c of section 92 c. Flanges of othersections of the clamp 90 would be similarly arranged in a facing, oropposing manner. The opposing flanges of adjacent clamp sections arejoined together using a number of bolts 96 (or “clamping bolts”) thatextend through bolt holes provided in the flanges. The flanges are thensecured together by nuts 98 that cooperate with the bolts 96. In thismanner, the opposing flanges of each clamp section are secured together,thereby forming the clamp 90. As the flanges of the clamp sections areurged together, the internal diameter of the clamp 90 is graduallyreduced. Thus, by appropriately sizing the clamp 90 with respect to theouter diameter of the pipe 12, the clamp 90 can be secured to the pipe12 outer surface, whereby relative movement between the pipe 12 and theclamp 90 is prevented. It will be understood that in order for suchtight fit to occur, there should be provided some clearance between theclamp sections to allow a reduction in the inner diameter of the clamp90 once positioned over a pipe 12. It will also be understood that byproviding bolts 96 of sufficient length, one clamp 90 may be used for arange of outer diameters of pipes.

The sections forming the clamp 90 are also each provided with a radiallyextending, circumferential “sealing” flange section 100, extending alongthe length of each section and extending between the opposing connectingflanges. The term “radially extending, circumferential” refers to theorientation of the sealing flange, wherein, when the clamp 90 isassembled and in use, each flange section extends radially away from thepipe and perpendicular to the longitudinal axis of the pipe 12. The term“sealing” refers to the use of such flange section in securing a sealingplate (described below) against the open end of the pipe 12. As shown inFIG. 10, clamp sections 92 a, 92 b and 92 c are provided, respectively,with sealing flange sections 100 a, 100 b and 100 c. For convenience,the circumferential sealing flange formed by the respective sectionswill be identified with element number 100. In the assembled state ofthe clamp 90, the sealing flanges sections of the clamp sections combineto form a radially extending sealing flange 100 on the clamp, whereinsuch flange extends radially outwardly away from the pipe 12 andtransverse to the longitudinal axis of the pipe 12. In this manner, whenthe clamp 90 is assembled on a pipe, the sealing flange sections of eachclamp section align over the circumference of the pipe 12 to form agenerally unitary flange 100. The sealing flange sections of the clampsections are also provided with a number of bolt holes 102, which arediscussed further below.

In order to seal the open end of the pipe 12, a sealing plate 104 isprovided. The sealing plate 104 is preferably sized to have a diameterthat is greater than the diameter of the pipe 12. Along the outer edgeof the sealing plate are provided a number of bolt holes 106 that arepositioned to cooperate with the bolt holes 102 provided in the sealingflange 100. As discussed above with respect to other embodiments, inuse, once the clamp 90 has been secured to the outer surface of the pipe12, the sealing plate 104 is then secured to the clamp 90. In thisprocess, the sealing plate is positioned against the opening of the pipe12 and a plurality of bolts (not shown) are passed through aligned boltholes, 102 and 106, of the sealing plate 104 and the sealing flange 100.Such bolts may be referred to herein as “sealing bolts”. As discussedabove, the sealing plate 104 is preferably provided with a sealing meansfor sealingly engaging the open end of the pipe 12. In one aspect, thesealing plate may be provided with a groove or race (not shown in FIG.10 but shown by example in FIGS. 7-9) and an appropriate sealing memberfor engaging and sealing the open end of the pipe. In operation, thesealing plate 104 is brought against the open end of the pipe 12 by, forexample, causing the end of the pipe to be received in the grooveprovided on the sealing plate 104. The bolt holes 106 of the sealingplate 104 are then aligned with bolt holes 102 of the sealing flange100. The sealing bolts (not shown) are then passed through the alignedbolt holes 102 and 106 and secured with nuts (not shown). As describedabove, tightening of the nuts results in the sealing plate 104 beingurged towards the clamp 90 and, due to the immobilization of the clamp90 on the pipe 12, the sealing plate 104 is thereby urged against theend of the pipe 12. The nuts are tightened until a sufficient seal isprovided for the open of the pipe 12. Once in this state, the interiorof the pipe may then be pressurized for conducting a test or any otherpurpose. The sealing plate 104 may be provided with one or more ports108 to which may be connected pressurizing means, pressure gauges or anyother instrument or apparatus.

As also shown in FIG. 10, in some instances, a reinforcement apparatus110 may be used within the interior of the pipe so as to brace againstthe compressive forces of the clamp 90. In one example, thereinforcement apparatus 110 comprises a plurality of radially extendingarms 112 connected together at a central hub 114. The hub 114 wouldgenerally be positioned on the longitudinal axis of the pipe 12. Theends of the arms 112 opposite the hub 114 preferably terminate in a pad116 adapted to bear against the inner surface of the pipe 12. Each ofthe arms are provided with tensioning means 118 that serve to lengthenthe arms so as to force the pads 116 against the wall of the pipe 12. Inone aspect, the tensioning means 118 are formed by a combination of thearms 112 having a threaded portion and lengthening nuts associated withsuch threaded portions. Such means of lengthening a rod are known in theart. Similarly, any other means of lengthening the arms 112 may be usedand the invention is not limited to any particular means for achievingsuch purpose. In certain cases, such as for example with large diameterpipes, the arms 112 of the reinforcement apparatus 110 may be providedwith a support ring 120 to prevent or reduce movement of the arms 112outside of the plane of the reinforcement apparatus 110. It will beunderstood that any number of arms 112 may be provided on thereinforcement apparatus 110.

As will be understood, in use, the reinforcement apparatus 110 would bepositioned inside of the pipe 12 prior to placement of the sealing plate104. Moreover, the reinforcement apparatus 110 would be positioned priorto establishing the clamping force of the clamp 90 on the pipe 12. Inthis way, as the clamp 90 is tightened over the outer wall of the pipe12, the reinforcement apparatus 110 serves to prevent any inwarddeflection or deformation of the pipe 12.

In some cases, the inner surface of the clamp 90 (or 68 d) may beprovided with a gripping means such as teeth or ribs etc. However, in apreferred embodiment, the inner surface of the clamp (90, 68 d etc.) issmooth as to prevent damage to the surface of the pipe 12.

FIG. 11 illustrates another embodiment of the invention described inFIG. 10. In FIG. 11, the clamp 90 is shown as above, provided over apipe 12 and proximal to an open end of the pipe to be sealed. However,as shown, a further circumferential clamp 122 is provided adjacent tothe clamp 90. The clamp 122 is of the same general construction as clamp90 described above. As illustrated, clamp 122 is positioned on the sideof the clamp 90 opposite the opening of the pipe 12. As will beunderstood, the additional clamp 122 provides added clamping force. Inorder to establish a physical connection between the clamps, clamp 90 isprovided with an additional radially extending circumferential flange124 on a side opposite to the flange 100 described above. Clamp 122includes at least one radially extending circumferential flange 126, onthe side adjacent to the clamp 90. The flanges 124 and 126 are providedwith a plurality of bolt holes that are aligned during installation soas to allow bolts 128 to extend there-through. Nuts 130 cooperate withthe bolts 128 to securely connect the clamps 122 and 90 together.Preferably, bolt holes 128 are evenly spaced along the circumference ofthe flanges 124 and 126. As will be understood, connection of the clamps122 and 90 serves to provide additional clamping force since theclamping surface area is increased. In the above description, the clamps122 and 90 and the respective flanges 124 and 126 have been described asingular elements. However, as described above, each is comprised of twoor more clamp sections that are connected together to form suchelements. As shown in FIG. 11, the clamp 122 may be provided with afurther radially extending circumferential flange 125 to which anotherclamp may be connected if necessary. It will be understood that anynumber of clamps can be combined in order to provide any desired levelof clamping force.

As also shown in FIG. 11, the sealing plate 130 comprises a bell-shapedelement. The sealing plate 130 functions in the same manner as thesealing plate 104 described previously. However, the curved, oroutwardly convex structure of the plate 130 allows, for example, anumber of ports 132, 133, 134 to be provided over the surface thereof.The sealing plate 130 is secured to the clamp 90 using bolts 136 andassociate nuts as described previously.

FIG. 12 provides an isolated view of a clamp such as clamp 90 or 122shown in FIGS. 10 and 11. As seen, the clamp of FIG. 12 is comprised ofsix essentially identical sections 92. For convenience, when referringto the clamp sections collectively (or portions of such clamp sections),the element number 92 is used without the letter suffixes. Each sectionincludes a curved inner surface 97 adapted to conform to the outersurface of a pipe (not shown) to which the clamp is to be secured. Asdescribed above, each section includes opposing radially extending,longitudinal connecting flanges 94 and 95, which, when the clamp isassembled, are placed in opposing arrangement as shown in FIG. 12. Bolts96 and associated nuts 98 serve to connect each section 92 together soas to form the clamp 90 for circumferentially fitting over the surfaceof a pipe. As described above, a space is preferably provided between atleast some of the adjacent clamp sections 92 so as to allow sufficientclearance for the sections to be tightened towards each other, andthereby, tightened over the outer surface of the pipe. Such tighteningserves to provide the necessary clamping force over the circumference ofthe pipe. Each of the sections 92 further includes a radially extending,circumferential sealing flange section 100 that is adapted to engage thesealing plate when the clamp is in use (as discussed above).

FIGS. 13 and 14 illustrate another embodiment of the invention. As shownthe embodiment of FIGS. 13 and 14 functions in effectively the samemanner as above. That is, in general, a pipe 12 is provided with acircumferential clamp 150 proximal to an open end of the pipe. The clamp150 is tightened over the outer surface of the pipe 12 so as to securesame and to prevent relative movement between the clamp and the pipe 12.As shown in FIG. 13, a sealing plate 152 is provided against the openend of the pipe 12 and subsequently secured to the clamp 150.

As shown in FIG. 13, the clamp 150 of this embodiment is operabledifferently from that of the previous figures. Specifically, the clamp150 is comprised of two or more clamp sections. In the embodiment shownin FIGS. 13 and 14, the clamp 150 is comprised of two sections, 154 and155. As described above, the clamp may be formed using any number ofsections, depending upon, inter alia, the size of each section and theouter diameter of the pipe in question. In the case where the clamp 150is formed in two sections, it will be understood that each section willhave a generally “C” shaped structure as shown in FIG. 14. In caseswhere a plurality of clamp sections are required, it will be understoodthat the shape of the sections will vary. The sections 154 and 155include radially extending, longitudinal “connecting” flanges. Thus, forsection 154, the connecting flanges are shown at 156 and 158. Forsection 155, the connecting flanges are shown at 157 and 159. Each ofthe connecting flanges 158 to 159 are provide with bolt holes,positioned so as to be aligned when the clamp is in use. In suchposition, “clamping” bolts 160 and 162 are inserted through the boltholes of opposed connecting flanges of adjacent clamp sections. Nuts 161and 163 are provided on the clamping bolts 160 and 162, respectively, soas to secure the connecting flanges against each other. Thus, as shownin FIG. 14, bolts 160, in combination with nuts 161, serve to secure theconnecting flanges 156 and 157 together. Similarly, bolts 162 and nuts163 serve to secure the connecting flanges 158 and 159 together. In thismanner, the sections of the clamp 150 are joined together to form agenerally annular shaped structure forming a concentric ring over theouter circumference of the pipe 12.

Once the sections forming the clamp 150 have been assembled as discussedabove, the clamp 150 is then secured to the outer surface of the pipe12. In order to achieve this, the clamp 150, once formed (by connectingthe respective clamp sections) is provided with two inner diameters, d1and d2, both of which are larger than the outer diameter of the pipe 12.As shown in FIG. 13, the first inner diameter, d1, is larger than thesecond inner diameter d2. When the clamp is in use, the section of theclamp having inner diameter d1 is positioned proximal to the open end ofthe pipe 12. The opposite end of the clamp (i.e. opposite the open endof the pipe 12) is provided with the inner diameter d2. The clamp 150further includes a ramped surface 164 extending between the twodiameters d1 and d2. In a preferred embodiment, a shoe 166 is providedadjacent the ramped section 164. The shoe 166 serves to extend theramped surface 164. As will be understood by persons skilled in the artupon reviewing the present description, in other embodiments of theinvention, the shoe 166 may be omitted or substituted with other similarfunctioning elements. In this description, the shoe 166 is described asa unitary structure provided on the clamp. However, it will beunderstood that the shoe 166 may be formed as separate sectionsassociated with or integral with each of the sections forming the clamp150.

The clamp 150 is also provided with a gripper ring 170, which is formedby at least two sections that are separated by spacing. For convenience,the gripper ring 170 will be discussed further as a unitary element. Asshown in FIG. 13, the gripper ring 170 has a generally annular ringshape preferably with a constant inner diameter capable of sliding overthe outer circumference surface of the pipe 12. The outer surface of thegripper ring 170 is provided with a ramped structure oppositely orientedto the ramped section 164 of the clamp 150. As shown in FIG. 13, thisresults in the gripper ring 170 having a varying outer diameter, whichis greater at the proximal end, proximal to the open end of the pipe 12,and less at the distal end, opposite to the open end of the pipe 12. Theouter surface of the gripper ring is thereby provided with a rampedsurface 171. As shown, the distal end of the gripper ring 170 is adaptedto be received under the ramped section 164 of the clamp and, wherepresent, under the shoe 166. When the clamp 150 is in position, thegripper ring 170 is positioned proximal thereto, thereby placing thegripper ring closer to the opening of the pipe 12 (as shown in FIG. 13).In this way, as the gripper ring 170 is advanced axially in the distaldirection over the pipe 12, i.e. away from the pipe opening and againstthe clamp 150, the gripper ring 170 is urged inwardly due to theinteraction between the opposed ramped sections 171 and 164. In thelatter case, it will be understood that the ramped surface 164 will bereflected in the structure of the shoe 166 and, where such shoe ispresent, the inward deflection of the gripper ring 170 would be causedby interaction with such shoe.

The clamp 150 further includes a radially extending, circumferentialsealing flange 174. As shown in FIG. 14, the sealing flange 174 iscomprised of flange sections 175 and 176, provided, respectively, onclamp sections 155 and 154. For convenience, the flange 174 will bedescribed as a unitary structure but will be understood to have suchgeneral structure once the clamp 150 is assembled.

A plurality of “gripper” bolts 178 extend through openings 180 in theflange 174. The gripper bolts 178 extend through the openings 180 in theproximal to distal direction (i.e. along the axis of the pipe 12, whenthe clamp 150 is in the assembled state there-over), wherein the boltheads are proximal to the opening of the pipe 12. The terminal ends ofthe gripper bolts 178 are adapted to bear against the proximal ends ofthe gripper ring 174. Thus, in this arrangement, tightening of the bolts178 forces the gripper ring 170 against the inner surface of the clamp150 and, therefore, under the ramped surface 164 thereof or the shoe166. In either case, the gripper ring 170, being of at least twosections, is deflected inwardly and forced against the outer surface ofthe pipe 12. With sufficient force applied by the tightening bolts, thegripper ring 170 is pressed tightly against the pipe surface to create astrong clamping force. This is continued until a sufficient clampingforce is achieved wherein relative axial movement of between the clamp150 and the pipe 12 is prevented.

In one aspect, the bolts 178 are received within cooperatively threadedopenings 180. In other aspects, a nut and threaded rod arrangement canbe used to achieve the same purpose. In other aspects, the bolts 178 maybe replaced with hydraulic rams or magnetically driven rods etc. It willbe appreciated that the invention is not limited to any specific meansof advancing the gripper ring 170. The bolts 178, and correspondinglythreaded openings 180, provide one such means. As shown in FIG. 14, aplurality of bolts 178 are provided and are generally equally spacedcircumferentially over the clamp. Such an arrangement is preferred sinceit serves to advance the gripper ring 170 equally over the circumferenceof the clamp 150.

The circumferential sealing flange 174 is also provided with a pluralityof generally circumferentially spaced bolt holes 182. Similarly, thesealing plate 152 is also provided with corresponding bolt holes 184.When the apparatus of the invention is positioned on the pipe 12, thesealing plate 152 is oriented so as to align bolt holes 184 with boltholes 182 provided on the flange 174. Once in this orientation,“sealing” bolts 186 are inserted through bolt holes 184 and 182 and nuts188 are used to urge sealing plate 174 towards the clamp 150. Asdiscussed in reference to other embodiments of the invention, thesealing plate 152 is preferably provided with a groove or race 190having dimensions sufficient to receive the open end of the pipe 12therein. In order to form a secure seal between the sealing plate 152and the open end of the pipe 12, a sealing material 192 is preferablyprovided within the groove 190. The sealing material may be an O-ring, agasket material or any other sealing material as described herein or aswould be apparent to persons skilled in the art.

In operation, the apparatus illustrated in FIGS. 13 and 14 are utilizedas follows. Firstly, as described above, the clamp 150 is assembled fromthe two or more pieces (described above) over the outer surface of thepipe 12, adjacent to an opening thereof. The sections of the gripperring 170 are positioned adjacent the clamp 150. As noted in FIG. 13, thesections of the gripper ring 170 are positioned so that the portionhaving the smaller outer diameter is distally oriented, away from theopening and towards the clamp 150. Thus, the gripper ring 170 ispositioned so as to align its ramped section 171 in an opposite manneras compared to the ramped section 164 of the clamp 150. Thus, thethinner portion of the gripper ring 170 is positioned to be receivedwithin an annular space created by the outer wall of the pipe 12 and thelarger inner diameter portion of the clamp 150.

Once the clamp and gripper ring sections are assembled in the desiredposition over the pipe 12, the clamp sections are secured together bymeans of clamping bolts 160, 162 and the associated nuts 161, 163,respectively. This results in the clamping sections being urged togetherthereby also causing the gripper ring sections to be urged together. Theclamp sections may optionally be provided with spacers 181 such as thatshown in FIG. 14. Such spacers serve to limit the amount of compressionexerted by the clamp 150 over the gripper ring 170. In such manner, thedesired clamping force on the clamp would be controlled by the gripperbolts 178 as discussed further below.

Once the clamp 150 is assembled over the pipe 12 as discussed above, thegripper bolts 178 are then tightened so as to force the gripper ring 170towards the clamp 150 and against the ramped portion 164 or, wherepresent, the shoe 166, which is provided with an equally ramped surface.In the process, the gripper ring 170 is radially compressed and therebyforced against the outer wall of the pipe 12. Further tightening of thebolts 178 creates a tight fit between the gripper ring 170 and the wallof the pipe 12, thereby preventing relative axial movement between theclamp 150 and the pipe 12. Once the clamp 150 is thus anchored to thewall of the pipe 12, the sealing plate 152 is positioned and alignedwith the circumferential flange 174 of the clamp 150. Tightening of thenuts 188 over the sealing bolts 186 urges the sealing plate towards theclamp 150 (which is clamped on the pipe 12) and, in the result, forcesthe sealing plate 152, and in particular the groove or race 190 thereof,against the open end of the pipe 12. The nuts 188 are tightened untilthe desired degree of sealing is achieved. With the sealing means 192 isplace, a sealing arrangement is achieved between the open end of thepipe 12 and the sealing plate 152. At this point, the interior of thepipe 12 may be pressurized and subjected to pressure testing for itsintegrity.

FIGS. 15 to 22 illustrate features of another embodiment of theinvention. As shown in FIG. 15, the apparatus of the invention includesa clamp 200 that is adapted to be secured to the outer wall of a pipe12. The clamp includes a first, or squeeze ring 202 and a second, orclamping ring 204. The first and second rings 202 and 204 are preferablyunitary structures that are generally annular in shape. The rings 202and 204 have respective internal and external diameters, with theinternal diameters of each being slightly larger than the outer diameterof the pipe 12 so as to allow the rings to be slidably provided over thepipe. The clamp 200 further includes a generally annular gripper ring206, which also has an internal diameter and an external diameter. Theinternal diameter of the gripper ring 206 is reducible, as describedfurther below. However, in its initial state, the internal diameter ofthe gripper ring 206 is greater than the external diameter of the pipe12 so as to allow the ring 206 to be slidably provided thereover.Gripper ring 206 is preferably formed of two or more sections. As shownin FIG. 20, the gripper ring 206 is formed, according to one embodimentof the invention, in two sections 206 a and 206 b. The purpose of suchmultiple sections for the gripper ring 206 will become apparent in thefollowing description.

As shown in FIG. 15, the clamp 200 is formed by first providing thesqueeze ring 202 over the outer surface of the pipe 12. This is achievedby sliding the ring 202 over the pipe, adjacent an open end thereof. Thegripper ring 206 is next positioned adjacent the squeeze ring 202. Asmentioned above, the gripper ring 206 is preferably provided in two ormore sections. Next the clamping ring 204 is positioned over the pipe asshown in FIG. 15. The squeeze ring 202 and clamping ring 204 are eachprovided with a plurality of bolt holes, 208 and 210, respectively, asshown in FIGS. 16 and 18. In positioning the portions of the clamp 200over the pipe, the bolt holes 208 and 210 of the squeeze ring 202 andclamping ring 204 are aligned. Once in this position, “clamping” bolts212 are inserted into the aligned bolt holes and such bolts aretightened with nuts 214. As will be understood in reviewing FIG. 15, asthe nuts 214 are tightened, the clamping plate and squeeze plate areurged towards each other to produce the required clamping force tosecure the clamp 200 over the outer diameter of the pipe 12.

The squeeze ring 202 is preferably provided with a beveled innerdiameter. Thus, the internal diameter of the squeeze ring 202 isprovided with a ramped surface 214 (as shown in FIGS. 15 and 17), suchthat a smaller inner diameter is provided distal to the open end of thepipe 12 and a larger inner diameter is provided proximal to such openend. The gripper ring 206 also comprises a generally annular shapedstructure but having a generally constant inner diameter, which facesthe outer surface of the pipe 12 when the apparatus is in use. The outerdiameter of the gripper ring 206 includes a ramped surface 216 (as shownin FIGS. 15, 21 and 22). This results in the gripper ring 206 having alarger outer diameter proximal to the opening of the pipe 12 and asmaller outer diameter distal to the pipe opening. The clamping ring 204is generally annular in shape is does not necessarily include anybeveled or ramped surfaces. However, the inner diameter of the clampingring 204 is smaller than the outer diameter of the gripper ring 206.This arrangement of the squeeze ring, gripper ring and clamping ring isshown in FIG. 15.

As shown, in assembling the apparatus over a pipe 12, the squeeze ring202 is first slid over the pipe 12, followed by the gripper ring 206 andfinally the clamping ring 204. It is noted that the thin, distal portionof the gripper ring 206 is adapted to be inserted between the proximalend of the squeeze ring 202 and the outer wall of the pipe 12. As thenuts 214 are tightened and the squeeze ring 202 is advanced against theclamping ring 204, the gripper ring 206 is therefore urged against theouter wall of the pipe 12. The proximal end of the gripper ring 206 isbiased against the clamping ring 204 and, therefore, prevented fromaxial movement with respect to the clamping ring. As explained above,the gripper ring 206 is preferably provided in two or more sections, asillustrated in FIG. 20. Where the gripper ring 206 is provided in twosections, as shown in FIG. 20, each of such sections 206 a and 206 bhave a generally arc shaped structure. The ends of each section, 206 aand 206 b, are preferably separated by space 207. The spaces 207 allowthe sections of the gripper ring 206 to be moved radially inwardlytowards each other, thereby resulting in a reduction of the innerdiameter of the gripper ring 206. Thus, as the gripper ring 206 is urgedtowards the wall of the pipe 12, the sections forming the gripper ring206 are urged together, thereby reducing the inner diameter of theannular gripper ring 206 and radially compressing the gripper ring 206over the outer wall of the pipe 12 to form a tight, clamping engagementtherewith. Thus, tightening of the nuts 214 results in the clamp 200being secured to the pipe wall so as to prevent relative axial movementthere-between.

Returning to FIG. 15, the apparatus of the invention is also providedwith a sealing plate 220, which functions generally in the same manneras described previously with respect to other embodiments. In theembodiment of FIG. 15, the sealing plate 220 includes a flange portion222 having an outer diameter greater than that of the pipe 12 and aninner diameter less than that of the pipe 12. The flange portion 222 isprovided with a groove or race 224 that is adapted to receive the openend of the pipe 12. The groove 224 includes a sealing member or membrane226 that is capable of forming a seal between the groove 224 and theopen end of the pipe 12. The flange portion 222 includes a plurality ofbolt holes 228 for receiving “sealing” bolts 230. The sealing bolts 230are adapted to extend to the clamp 200 and be connected thereto. Nuts232 are also provided, which cooperate with the sealing bolts 230 toadvance the sealing plate 220 towards the clamp 200. In the result, thesealing plate is forced against the open end of the pipe 12 and theopening of the pipe is sealed within the groove 224. Such sealing actionis similar to that described above with respect to other embodiments ofthe invention. In one embodiment, the bolts 230 may be secured to theclamping ring 204 of the clamp. In another embodiment, as illustrated inFIG. 15, the sealing bolts 230 and clamping bolts 212 may comprise thesame entity. Thus, the single bolt serves to join the clamping andsqueeze rings together as well as to urge the sealing plate 220 towardsthe clamp 200. In such case, the bolts 217 are elongated and capable ofextending through the bolt holes 228 in the flange portion 222 of thesealing plate 220. Thus, the two sets of nuts 214 and 232 would engagethe same bolt but would serve to provide, respectively, the requiredclamping force and sealing force. It will be understood that the use ofa single set of bolts may be advantageous in terms of reducing thenumber of elements of the apparatus. However, the apparatus of theinvention will be understood to function equally with separate sealingand clamping bolts. In such case, two sets of circumferentially spacedbolt holes will be provided on the clamping plate 204. One set will beused to receive the clamping bolts 212 and the other set will be used toreceive the sealing bolts 230.

The sealing plate 220 also includes a body portion 234 that ispreferably integral with the flange portion 222. The body portion 234 ofthe sealing plate 220 may comprise a generally flat, plate-likestructure as described previously. However, in the embodiment shown inFIG. 15, the body portion 234 has convex shape, protruding beyond theopening of the pipe 12. The body portion 234 may then be provided with anumber of ports 236, to which may be connected pressurizing means (suchas a hose to supply a pressurizing fluid to the interior portion of thepipe 12), evacuation means (such as a hose to drain the pressurizedfluid from the pipe 12), pressure gauges, temperature gauges, reliefvalves etc. Various other devices for connection to the ports 236 willbe apparent to persons skilled in the art.

FIG. 23 illustrates a variation of the apparatus shown in FIG. 15, andillustrates another embodiment of the clamp, shown generally at 250. InFIG. 23, the sealing plate 220 is essentially the same as that discussedpreviously. Further, the clamping ring 204 of the clamp 250 is also asdescribed above. However, as shown, the clamp 250 of FIG. 23 is providedwith a plurality of squeeze rings 202 and gripper rings 206. As will beunderstood, by providing a plurality of squeeze and gripper rings, 202and 206, the amount of clamping force offered by the clamp 250 isincreased. In the result, the clamp of FIG. 23 is able to withstandhigher pipe pressures than the clamp of FIG. 15. The number ofadditional squeeze rings and clamping rings will vary based on thedesired clamping force required and it will be understood that anynumber of such rings may be provided for any given clamp.

In order to ensure that each squeeze ring 202 acts upon a respectivegripper ring 206, each of the squeeze rings 202 are separated by aseparation ring 252. As will be understood, the separation rings 252serve to prevent binding between each of the squeeze rings and to ensurethat each of such squeeze rings act upon respective gripper rings 206.The separation rings 252 may comprise, for example, O-rings.

It will be understood that in situations where a given length of a pipeis to be tested, both ends of the pipe can be sealed using any of thesealing apparatus described above. In such case, the ends of the pipewill each be provided with the same or different ones of the apparatusof the invention. Each end of the pipe would thus be sealed and theinterior of the pipe may then be pressurized for conducting an integritytest.

As described above, in some of the embodiments of the invention, theclamp includes a gripper plate (formed of two or more sections) that isprovided with a ramped surface adapted to engage an oppositely rampedsurface on another portion of the clamp. In some cases, such oppositelyramped surface is provided on the clamp body or on a “squeeze” ring asdescribed above. It will be noted in the described embodiments that thegripper plate is positioned so that the thinner portion of the gripperplate is oriented away from the pipe opening. As seen, for example inFIGS. 13 and 15, and as will be understood by persons skilled in theart, such an orientation would be preferred. Specifically, once theclamp is tightened against the exterior surface of the pipe, the clampwould be securely engaged and the sealing plate is then attached theretoso as to seal the open end of the pipe. Subsequently, when the interiorof the pipe is pressurized (such as in cases where a pressure test isconducted on the pipe), it will be understood that such pressure willact to force the sealing plate of the apparatus away from the pipeopening in the axial direction. However, since the sealing plate issecured to the clamp by means of the sealing bolts (i.e. the boltsconnecting the sealing plate to the clamp), the axial movement of thesealing plate would also exert an axial force on the clamp. In theresult, the clamp body or squeeze ring would be forced to travel overthe gripper ring due to the opposed ramped surfaces. As will beunderstood, such movement would cause the gripper ring to be furthercompressed against the external surface of the pipe and, thereby, resultin strengthening the gripping force between the gripper ring and theexterior of the pipe. Thus, even in the situation where a high pressureapplies an axial force on the clamp, a corresponding increase inclamping force results. The above mentioned orientation of the gripperring and the other clamp components comprises a preferred arrangement ofthe apparatus of the invention, so as to allow increased clamping forceupon application of an axial force (such as due to pressurization of thepipe). However, it will be understood that the orientation of thegripper ring and the clamp body or the squeeze ring may be reversedwhile still providing an adequate clamping force on the pipe. Forexample, such reversed orientation may be used in cases where the pipeis not pressurized or where the required pressurization is minimal.

In the above description, reference is made to the use of bolts forsecuring sections of the clamp together and for securing the sealingplate to the clamp. Such bolts are described as extending through boltholes provided in respective flanges. However, although such arrangementis preferred, it will be appreciated that other means may be used toachieve the desired purpose. For example, the respective flange may beurged together using compression clamps etc. Magnetic means may also beused to urge the respective elements towards each other. In addition,the above description has referred to the use of threaded bolts havingnuts provided on each end thereof. However, in another embodiment, thebolts may include heads, whereby only a single nut is required toachieve the required tightening. For this reason, the aforementionedbolts and equivalent elements that serve a connection function (i.e.connecting two or more other elements together) may be referred togenerally as “connecting elements”.

As illustrated in FIGS. 7 to 23 and as described above, thecircumferential clamp that is secured to the external surface of a pipe,is preferably positioned distally of the open end of the pipe by atleast a short distance. As will be understood, such positioning providesa degree of separation between the clamp and the sealing plate, therebyallowing the sealing plate to be sufficiently sealed against the end ofthe pipe without being hindered by the clamp itself. Furthermore, itwill be understood that placing a circumferential clamp close to an endof the pipe, and subjecting the pipe to a strong radially compressiveforce may damage the end of the pipe and prevent it from beingconnectable to other pipes or to other apparatus (such as vessels,flanges etc.). It will be understood that the above described internalreinforcement (such as shown at 110 in FIG. 10) may be used incombination with any of the external clamps described herein. Inaddition, having the ability to axially position the clamp at anylocation along the length of the pipe allows for a desired amount ofclearance in the event that a weld is located near the open end of thepipe.

It will be understood that the external clamp and sealing plate of theinvention can also be used on pipes that include a bend. For example, ina pipe comprising an elbow, the clamp may be positioned on one side ofthe bend with the sealing plate covering the pipe opening on an oppositeside of the bend. In such case, the connecting elements between theclamp and the sealing plate may be adapted or oriented to provide thesame sealing force as described above. For example, the clamp may beprovided with an extension for cooperating with the connecting elementsto engage the sealing plate. Various other such modifications to theinvention are also possible.

As discussed above, the apparatus of the invention is preferably usedfor sealing an end of a pipe so that the interior of the pipe can bepressurized such as for testing the integrity of the pipe. In oneexample, the integrity test is used for testing a weld that may bepresent on the pipe. Such a weld may serve to connect two pipe segmentsor to connect the pipe to another apparatus.

It will be understood that the above discussion has used geometric termssuch as annular, disc, circumference, etc., for ease of reference.However, these terms should not be construed as limiting the inventionto any specific shape of nozzle or pipe and various modifications of theapparatus will be apparent to persons skilled in the art to adapt sameto any shape or design.

Although the invention has been described with reference to certainspecific embodiments, various modifications thereof will be apparent tothose skilled in the art without departing from the purpose and scope ofthe invention as outlined in the claims appended hereto. Any examplesprovided herein are included solely for the purpose of illustrating theinvention and are not intended to limit the invention in any way. Anydrawings provided herein are solely for the purpose of illustratingvarious aspects of the invention and are not intended to be drawn toscale or to limit the invention in any way. The disclosures of all priorart recited herein are incorporated herein by reference in theirentirety.

I claim:
 1. An apparatus for sealing an open end of a pipe comprising:at least one generally annular shaped clamp having an inner diameteradapted to be provided over an outer surface of the pipe, the clampincluding a means for circumferentially gripping the outer surface ofthe pipe and preventing relative axial movement there-between; a sealingplate, adapted to cover and seal the open end of the pipe; an urgingmeans for urging the sealing plate axially towards the clamp and againstthe open end of the pipe when said apparatus is in use; the clampcomprising at least two clamp sections adapted to be joined together;each of the clamp sections including connecting flanges, provided atopposite ends of respective clamp sections; a plurality of firstconnecting elements for connecting the opposed flanges of adjacent clampsections, when the apparatus is in use, and for tightening adjacentclamp section together; each of the clamp sections including a sealingflange extending along at least a portion of the length thereof,wherein, when said clamp sections are assembled, said sealing flangesform a generally circumferential flange on the clamp.
 2. The apparatusof claim 1, wherein the sealing plate includes a groove for receivingthe open end of the pipe, the groove including a sealing means forforming a seal between the groove and the open end of the pipe.
 3. Theapparatus of claim 1, wherein the urging means comprises a plurality ofsecond connecting elements extending between the generallycircumferential flange of the clamp and the sealing plate, wherein, whensaid apparatus is in use, said second connecting elements are adapted toforce the sealing plate in a direction towards the generallycircumferential flange and against the open end of the pipe to form asealing engagement between the sealing plate and the open end of thepipe.
 4. The apparatus of claim 1 further comprising an internalreinforcement assembly for insertion within the pipe and for radiallybracing the wall of the pipe.
 5. The apparatus of claim 4, wherein theradial reinforcement assembly comprises a hub and a plurality of armsextending radially outwardly from the hub to the inner surface of thepipe wall, when said assembly is in use.
 6. The apparatus of claim 5,wherein the length of each of said arms is adjustable.
 7. The apparatusof claim 1, wherein the sealing plate includes at least one port forconnection to a pressurizing means, a monitoring means or a combinationthereof, for pressurizing, venting or monitoring the interior of thepipe.
 8. The apparatus of claim 1, wherein the clamp includes: agenerally annular body having an inner diameter surface, at least aportion of the inner diameter surface including a first ramp extendingfrom a first end to a second end of the annular body, the annular bodyhaving an inner diameter that is greater at the first end than at thesecond end; a generally annular gripper ring, coaxial with the annularbody, the gripper ring being comprised of two or more sections, andhaving an inner surface with an inner diameter for engaging the outersurface of the pipe, and an outer surface, at least a portion of theouter surface of the gripper ring including a second ramp, the secondramp extending from a first end of the gripper ring to a second end ofthe gripper ring, the second ramp being oppositely directed to the firstramp, wherein the second end of the gripper ring is insertable within anannular space between the first end of the annular body and the outerwall of the pipe; and, a means for urging the gripper ring and theannular body towards each other for forcing the second ramp under thefirst ramp, whereby, when the apparatus is in use, the first ramp bearsagainst the second ramp wherein the inner diameter of the gripper ringis reduced resulting in a frictional engagement between the gripper ringand the outer surface of the pipe.
 9. The apparatus of claim 8, whereinthe means for urging the gripper ring comprises a plurality of boltsprovided on the annular body, said bolts being arranged to apply anaxial force against the first end of the gripper ring.
 10. The apparatusof claim 8, wherein the sealing plate includes at least one port forconnection to a pressurizing means, a venting means, a monitoring meansor a combination thereof, for pressurizing, venting or monitoring theinterior of the pipe.
 11. The apparatus of claim 8 further comprising aninternal reinforcement assembly for insertion within the pipe and forradially bracing the wall of the pipe.
 12. The apparatus of claim 11,wherein the radial reinforcement assembly comprises a hub and aplurality of arms extending radially outwardly from the hub to the innersurface of the pipe wall, when said assembly is in use.
 13. Theapparatus of claim 12, wherein the length of each of said arms isadjustable.
 14. A method for sealing a section of a pipe having an openend, the method comprising: securing at least one external clampcircumferentially over the outer surface of the pipe at a locationspaced away from the open end, the clamp being frictionally secured tothe pipe surface so as to prevent relative axial movement between theclamp and the pipe; positioning a sealing plate against the open end ofthe pipe, for covering and sealing the open end of the pipe; connectingthe sealing plate to the clamp; forcing the sealing plate axiallytowards the clamp and forming a seal between the open end of the pipeand the sealing plate; wherein the clamp comprises a generally annularbody formed of at least two sections, and wherein the step of securingthe clamp over the outer surface of the pipe comprises connecting andtightening the at least two sections together to cause frictionalengagement between the clamp and outer surface of the pipe.
 15. Themethod of claim 14 further comprising pressurizing the interior of thepipe.
 16. The method of claim 14 further comprising positioning a radialreinforcement assembly within the pipe, at a location corresponding tothe clamp, for radially supporting the wall of the pipe.
 17. The methodof claim 14, wherein the clamp comprises: a generally annular bodyhaving an inner surface, a portion of the inner surface comprising afirst ramp; and, a generally annular gripping ring formed of at leasttwo sections, said gripper ring including an outer surface, a portion ofthe outer surface comprising a second ramp; the method comprising:coaxially positioning the annular body and the gripper ring over a pipesuch that the first and second ramps are oppositely oriented, whereinthe second ramp of the gripper ring is insertable between the first rampof the annular body and the outer wall of the pipe; forcing the gripperring against the annular body to cause radial compression of the gripperring and frictional engagement of the gripper ring over the pipe outersurface; and, forming a clamping force between the gripper ring and thepipe surface to prevent relative axial movement between the clamp andthe pipe.
 18. The method of claim 17, wherein the step of forcing thegripper ring comprises urging the gripper ring by a plurality of boltsconnected to the annular body.